Agriculture Reference
In-Depth Information
Chapter 7
1. Lapsley 1996.
2. The UC Davis Department of Viticulture and Enology provided early, critical
work to help growers recognize that quality winegrapes required different man-
agement practices than table or raisin grapes. It also conducted essential research
on varietals and their role in quality wine production.
3. Elizabeth Barham (2003) contrasts US and European understandings of
“terroir.”
4. For more on the dynamics of the California winegrape industry, see Warner
in review (b).
5. The grape leaf hopper (
Erythoneura elegantula
) is the primary insect pest for
Lodi grape growers, and the myramid wasp
Anagrus epos
can provide biological
control, although it does not do so consistently. Initially growers and researchers
were enthusiastic about the possibility of using French prune trees as hosts for
alternate, counter-seasonal prey for the
Anagrus
, but they discovered that to be
effective, growers would have to devote an equal area to prune trees as wine-
grapes, an impractical proposal for modern farming. On biocontrol of leaf
hoppers, see Murphy et al. 1996. Researchers had also hoped that cover crops
could be an alternate host for other beneficial insects, but they determined
instead that cover crops had an indirect effect on pest pressure through compet-
ing with vines for nutrients. Even though cover crops increase water use,
growers have determined their use resulted in a significant reduction in mites. On
cover crop/vine/insect pest relationships, see Costello and Daane 1998 and
Daane and Costello 1998. Growers express the most enthusiasm for deficit irri-
gation research demonstrating that by moderately stressing vines by withholding
irrigation water for a few weeks during the early summer months improves color
and flavors later in the season. Lodi growers now typically aim to harvest 5-7
tons per acre, a marked reduction from previous decades.
6. This periodization and most of the information in this section is taken from a
conference
Twelve years of sustainable viticulture in Lodi
, held March 24, 2004,
summarized in Ohmart 2004.
7. Ohmart 1998.
8. He said this at the “Twelve Years of Sustainable Viticulture in Lodi” meeting,
held March 24, 2004.
9. Arounsack et al. (2004) have studied decreases in FQPA priority herbicides
among Lodi BIFS growers. Organophosphate use in among Lodi winegrape
growers has dropped to virtually nil. This appears to be chiefly because: alterna-
tive pesticides have been developed (manufacturers do create new products for
larger California commodities like winegrapes); growers have realized
organophosphates are not necessary to grow quality winegrapes; for years the
commission has discouraged their use. The Vine Mealybug is beginning to infest
some vineyards in the district, and this has resulted in increased Lorsban use (an
organophosphate) because no softer products yet exist. Ohmart's analysis of
